This invention relates to sharpening tools and, in particular, to a tool for dressing a twist drill bit.
Most high speed twist drill bits have an elongated, generally cylindrical body with two helical channels, 180 degrees apart, extending substantially the length of the drill bit. The two helical channels terminate at a pointed leading edge forming two cutting surfaces.
Eventually, after a period of use, the drill bit cutting surfaces will become dull and require sharpening. When drill bits become dull they are typically ground to resharpen them. Grinding the drill bits removes a significant amount of drill bit material thus shortening the drill bit with each grinding, and consequently the life of the drill bit.
However, when drill bits become dull, they only have to be dressed, i.e., only enough material needs to be removed to generate a sharp cutting edge. Thus, by dressing rather than grinding, the life of the drill bit may be substantially increased. Material is removed from the drill bit without compromising the geometry of the drill bit.